I have a scenario that I could use anyone's help with. I understand the ARV x 70% - repair formula, but.....here is my dilemma.

I found a house owned free and clear by the seller and he's asking 89k cash. The house is located in an excellent neighborhood, located near a school, near supermarkets and stores, near downtown.  The comps that I had pulled, were of houses that sold around the area about 3-5 blocks away because no houses have sold within the past 6-12 months and there are no renters in that neighborhood where the house is actually located, and those houses were sold for around 55-65k. The house doesn't need many if any repairs.

Now I know every sell is different, and when to use the 70% rule depends on the deal and the situation. So I plugged the numbers in and they are as follow:

ARV - 65,000 x .7 = 45,500 - repair (i.e. 5,000) = (offer) 40,500

(based off comps)                  

Now where I'm getting twisted up is, If I offer $40,500 for the house and let's say its accepted.  As a wholesaler, where would my profit figure in for setting up the deal. 

Do I subtract 5-10k off the offer for my assignment fee and get it under contract for 30-35k and advertise it for 40-45k?

Do I add 5-10k to the offer for my assignment fee and advertise it for 45-50k

Also, when I divide 40,500 by 65,000 it comes to 62%. Is that the ROI that the investor will make.? Would this be considered a "good deal" for a investor?

I just need some advice from more experienced people to know if I'm on the right track or not.  I'm giving my heart & soul to learn about real estate investing and get it right. Your input would be very much appreciated.

Thank you